System and method to distribute power to both an inertial device and a voltage sensitive device from a single current limited power source

ABSTRACT

A system may regulate voltage supplied from a power source to an integrated circuit and/or an inertial device. A minimal voltage may be maintained in the integrated circuit by temporarily cutting off current to the inertial device to supply surges of voltage to the controller. Optionally voltage may be smoothed between said surges for example by adding capacitance and/or a current restrictor.

BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to a powerdistribution system and, more particularly, but not exclusively, to asystem and method to supply simultaneously from a single power source adesired voltage to a CPU and a power to an inertial device, for exampleto a controller and motor of an infusion device.

Portable devices often require powering of various components from asingle power supply. Under some conditions the power output of the powersupply may not simultaneously fill the needs of all of the components. Alarge number of devices exist for power regulation to solve thisproblem. In particular, portable infusion devices may have need forstrictly controlled and reliable pumping of medicine using a smalldisposable device.

US publication no. 2005/0038388 to Hommann et al. discloses an injectiondevice including a capacitor as an energy accumulator for providingenergy for performing an injection. In some embodiments, a voltageregulator, in particular a DCDC converter such as one of those known inthe electrical art, is preferably connected to the capacitor, such thata substantially constant DC voltage for operating the injection device,for example an electric motor associated with the injection device, canbe obtained from the variable DC voltage on the capacitor. Buckconverters and boost converters are known, using which a DC voltage canbe obtained above or below the input voltage. A buck-boost converter oran inverting circuit regulator can equally be used.

U.S. Pat. No. 4,126,132 to Portner and Jassawalla discloses anintravenous and ultra arterial delivery system having a disposablecassette actuated by a pump and control electronics for providingpositive but variable delivery rates. The electronics has low powerconsumption so as to be suitable for battery operation, such as by wayof rechargeable batteries.

US publication no. US 2010/0121277 to Fehr et al. discloses a medicalinfusion system with pulse width modulation and a safety circuit and amethod thereof. Embodiments of the system include a switching device anda pump motor, wherein the pump motor and the switching device areconnected in series and constitute a power supply circuit to beconnected to a power supply. Embodiments of the system further includesa control signal generator configured to generate a control signal e.g.PWM, and which is connected to input of the safety circuit. Output ofthe safety circuit is connected to a control input of the switchingdevice such that the pump motor will not operate if there is no controlsignal applied to the input of the safety circuit.

US Publication no. US 2009/0054832 to Sugimoto et al. discloses anadministration apparatus for medical use which is driven by an electricdriving source to perform administration of a drug. Low-speed operationduring air releasing operation is performed by PWM (Pulse WidthModulation) control.

Additional background art includes U.S. Pat. No. 5,683,367 to Jordan etal. and U.S. Pat. No. 6,270,478 to Mern.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of some embodiments of the present inventionthere is provided a method to increase a voltage potential available toan integrated circuit device sharing a battery power source with anactuator. The method may include producing transient high voltage surgesin the battery output by repeatedly cutting off power to the actuator.The method may further include storing energy during the surges andreleasing the stored energy to maintain an input voltage to theintegrated circuit above the threshold voltage when a voltage output ofthe battery falls below a threshold voltage.

According to some embodiments of the invention, the cutting off of powermay be controlled by the integrated circuit.

According to some embodiments of the invention, the method may furtherinclude preventing leakage of the released energy away from theintegrated circuit.

According to some embodiments of the invention, the repeatedly cuttingmay have a period of between 5 and 50 milli-seconds.

According to some embodiments of the invention, the repeatedly cuttingmay have a duty cycle of between 50% and 95%.

According to some embodiments of the invention, the method may furtherinclude pumping a medicine with the actuator and controlling a rate ofthe pumping with the integrated circuit.

According to some embodiments of the invention, the controlling may beadjusted for the maintaining the voltage threshold to the integratedcircuit. For example the adjusting may account for an output limitationof the battery and a limit of the storage.

According to some embodiments of the invention, the controlling may beby pulse density modulation.

According to some embodiments of the invention, the pulse densitymodulation may have a pulse width of between 50 and 500 milli-seconds.

According to some embodiments of the invention, the pulse densitymodulation may have a duty cycle of between 2% and 20%.

According to some embodiments of the invention, the method may furtherinclude testing a voltage input to the integrated circuit and adjustingthe cutting off of power to the actuator according to a result of thetesting in order to maintain a threshold voltage to the integratedcircuit.

According to some embodiments of the invention, the adjusting of thecutting off of power may include lengthening a period of the cutting offin response to a low voltage measurement, shortening a period betweenthe cut off periods in response to a low voltage measurement and/orreducing a duty cycle of the actuator in response to a low voltagemeasurement.

According to some embodiments of the invention, the method may furtherinclude storing performance data in a non-volatile memory when there islow voltage input to the integrated circuit. The method may furtherinclude restarting the system after a shut down and checking theperformance data after the restarting. The cutting off of power to theactuator upon the restart may be adjusted according to the performancedata to prevent further failure.

According to some embodiments of the invention, the performance data mayinclude a voltage output of the battery, a voltage input of theintegrated circuit and/or a current input to the actuator.

According to some embodiments of the invention, the adjusting mayinclude lengthening a period of the cutting off in response to a lowvalue of the voltage input measurement, shortening a period between thecut off periods in response to a low value of the voltage inputmeasurement, reducing a duty cycle of the actuator in response to a lowvalue of the voltage input measurement, lengthening a period of thecutting off in response to a low value of the voltage outputmeasurement, shortening a period between the cut off periods in responseto a low value of the voltage output measurement and/or reducing a dutycycle of the actuator in response to a low value of the voltage outputmeasurement.

According to an aspect of some embodiments of the present inventionthere is provided a system to distribute power among a plurality ofcomponents of a portable device. The system may include a first circuitpowering an electrical actuator and a second circuit powering anintegrated circuit. The system may also include a power distributorconnected to a battery. The power distributer may be configured tosupply to the first circuit, higher current pulses of power from thebattery having sufficient energy to power the actuator, and to at leastpartially cut off power to the first circuit between the pulses toproduce voltage surges having sufficient energy to power the integratedcircuit at a higher voltage potential than the higher current pulses.

According to some embodiments of the invention, the system may furtherinclude an energy storage device connected to the second circuit. Theenergy storage device may be configured to store energy at a highvoltage during the voltage surges, and to release the stored energy tothe integrated circuit between the voltage surges.

According to some embodiments of the invention, the actuator may includea medicine pump and the integrated circuit may include a controller forthe pump.

According to some embodiments of the invention, the distributer may becontrolled by the integrated circuit.

According to some embodiments of the invention, the system may furtherinclude a sensor to sense a voltage input to the integrated circuit. Theintegrated circuit may be configured to adjust the distributer inresponse to an output of the sensor to preserve a threshold voltage tothe integrated circuit.

According to some embodiments of the invention, the system may furtherinclude a restrictor to prevent power leakage from the integratedcircuit to the actuator.

According to some embodiments of the invention, the restrictor mayinclude a diode and/or an electronic switch.

According to some embodiments of the invention, the integrated circuitmay be configured to adjust the distributer in response to an aging ofthe battery.

According to some embodiments of the invention, the actuator may have aninertia to keep running over an inertial period. The distributer may beconfigured to keep a length of a cut off period between the high currentpulses less than a length of the inertial period.

According to some embodiments of the invention, system may furtherinclude a voltage sensor configured to measure an input voltage to theintegrated circuit. The integrated circuit may be configured to receiveoutput from the sensor and to adjust the distributor in response to theoutput of the sensor to maintain the input voltage greater than athreshold value.

According to some embodiments of the invention, the adjusting mayinclude lengthening a period of the cutting off in response to a lowvalue of the voltage input measurement, shortening a period between thecut off periods in response to a low value of the voltage inputmeasurement, reducing a duty cycle of the actuator in response to a lowvalue of the voltage input measurement, lengthening a period of thecutting off in response to a low value of the voltage outputmeasurement, shortening a period between the cut off periods in responseto a low value of the voltage output measurement, and/or reducing a dutycycle of the actuator in response to a low value of the voltage outputmeasurement.

According to some embodiments of the invention, the system may furtherinclude a sensor configured to measure a voltage output of the batteryand/or a current input of the actuator. Operation of the distributor maybe adjusted according to an output of the sensor.

According to some embodiments of the invention, the system may furtherinclude a non-volatile memory. The memory may be configured to store aperformance parameter. The integrated circuit may be configured to readthe non-volatile memory upon a start up of the system and to adjust anoperation of the distributor in response to the performance parameter.

According to some embodiments of the invention, the performanceparameter may include a voltage output of the battery, a voltage inputof the integrated circuit, a current input of the actuator, a number ofrotations of a motor and/or a preprogrammed parameter.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

Implementation of the method and/or system of embodiments of theinvention can involve performing or completing selected tasks manually,automatically, or a combination thereof. Moreover, according to actualinstrumentation and equipment of embodiments of the method and/or systemof the invention, several selected tasks could be implemented byhardware, by software or by firmware or by a combination thereof usingan operating system.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe invention, will be better understood when read in conjunction withthe appended drawings. For the purpose of illustrating the invention,there are shown in the drawings embodiments which are presentlypreferred. It should be understood, however, that the invention is notlimited to the precise arrangements and instrumentalities shown.

In the drawings:

FIG. 1 is a flow chart illustrating an exemplary embodiment of a methodof providing power to multiple devices;

FIG. 2 is a circuit diagram of an exemplary embodiment of a system toprovide power to two devices;

FIG. 3A is a graph showing experimental results of voltage over time totwo devices powered by an exemplary embodiment of a method of providingpower to multiple devices;

FIG. 3B is an expanded scale schematic diagram showing details ofvoltage over time to two devices powered by an exemplary embodiment of amethod of providing power to multiple devices;

FIG. 3C is a schematic diagram showing details of voltage over time totwo devices powered by an exemplary embodiment of a method of providingpower to multiple devices;

FIG. 3D is a large scale schematic diagram showing a few cycles ofvoltage over time to two devices powered by an exemplary embodiment of amethod of providing power to multiple devices;

FIG. 3E is a diagram on off cycles for an exemplary embodiment ofvariable length power cycles;

FIG. 4 is a block diagram of an infusion pump employing an exemplaryembodiment of a system to provide power to two devices;

FIG. 5 is a flow chart illustration of dynamic adjustment of a system toprovide power to two devices;

FIG. 6 is a graph showing experimental measurements of voltage overtime, and current over time, and testing times in an exemplaryembodiment of a method of providing power to multiple devices;

FIG. 7 is a detailed circuit diagram of an exemplary embodiment of asystem to provide power to two devices;

FIG. 8 is a detailed circuit diagram of an exemplary embodiment of asystem to provide power to two devices;

FIG. 9 is a circuit diagram of an exemplary embodiment of a system toprovide power to two devices including an optional boost regulator, and

FIG. 10 is a large scale schematic diagram showing a few cycles ofvoltage over time to two devices powered by an exemplary embodiment of amethod of providing power to multiple devices with a large duty cycle.

DETAILED DESCRIPTION OF THE INVENTION

The present invention, in some embodiments thereof, relates to a powerdistribution system and, more particularly, but not exclusively, to asystem and method to supply simultaneously from a single power source adesired voltage to a CPU and a power to an inertial device, for exampleto a controller and motor of an infusion device.

Overview

It is sometime desirable to power two devices from a single powersource. In some cases, the output of the power source may be limited,for example, the output voltage of a battery may be dependent on thecurrent drawn.

In some cases, the power output function of the power supply may not besuited to supply directly the simultaneous power requirements ofdifferent components. For example, in some embodiments, it may bedesired to simultaneously supply high current to an inertial device andhigh voltage to a processor. Some embodiments of a battery may becapable of supplying a high current at a low voltage (that mayoptionally be sufficient for the inertial device) or a low current at ahigh voltage (that may optionally be sufficient for the processor).Nevertheless, the battery may be limited in its ability to directlysupply high current at a high voltage sufficient time to both componentsover a long time period.

In some embodiments of the current invention the output of a powersupply may optionally be distributed in time to supply the variouscomponents. Optionally, a high power component (for example an actuatorincluding for example a DC motor) may be driven with pulses of power. Insome embodiments, a component requiring high voltage (for example anintegrated circuit including for example a CPU) may be powered by highvoltage surges that may occur while power to the motor is cut offbetween the pulses.

Optionally, power interruptions may be short enough for the devices tocontinue functioning (for example the motor may continue to spin due toinertia between pulses). Optionally, an energy storage device (forexample a capacitor) may be supplied to smooth out interruptions (forexample to stabilize voltage to a CPU between voltage surges).

In some embodiments, the current distribution may be tuned to preserve avoltage input to the integrated circuit and not necessarily to achieve aparticular speed or output or performance of the motor. For example thedistribution parameters (frequency, duty cycle etc.) may be fixed (forexample to achieve a reliable minimal CPU input voltage under a varietyof conditions). Alternatively or additionally, the distributionparameters may be adjusted according to the CPU input voltagerequirements regardless of the motor performance (within limits).Alternatively or additionally, the distribution parameters may bedynamically adjusted while the system is running according to the CPUinput voltage requirements with some limitations based on minimalstandards of the motor performance.

In various embodiments, pulses of power to the motor may last fromexample from 5-50 msec. The pulses may supply the motor with a highcurrent of for example from 100-400 mA, for example at start up. Thebreaks between pulses may be, for example, between 1-15 msec.Optionally, a CPU reset threshold may fall between 1.5 and 3.5 V.Optionally a CPU may draw between 0.1 and 1.0 mA. Optionally, a motormay draw, for example, current ranging between 30 and 200 mA whilerunning.

In some embodiments, the pulses may be simple and/or fixed. For examplethe pulse length and/or the length of time between pulses and/or theduty cycle of the system may be fixed. Additionally or alternatively theoscillator may be programmable or adjustable prior to operation tocompensate for conditions of the system (for example aging of a batteryor a high load on a motor) or operating conditions (for example shortterm or long term operation). Additionally or alternatively, theoscillator may be dynamically adjustable during operation.

In some embodiments, the current invention may be capable of very highefficiency (efficiency here is defined as power input to the activedevices [e.g. the motor and the CPU] divided by the power output of thebattery). For example, while the motor is stopped, the system may havean efficient greater the 98%.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings and/or the Examples. The invention iscapable of other embodiments or of being practiced or carried out invarious ways.

An Exemplary Method of Powering Two Devices

FIG. 1 illustrates an exemplary embodiment of method supplying 112 powerto two devices with a single, current limited power source, for examplea battery. Optionally, power is distributed in time. For example duringa first time period the battery drives a high current low voltagedevice. Optionally, during a second period, power is cut off to the highcurrent device. During the cut off period, in some embodiments, thevoltage output of the battery may surge. The high voltage battery outputduring the surge period may be used for example to power a seconddevice, for example a CPU requiring high voltage and low current. Insome embodiments, during the cut off period, power to the high currentdevice may be only partially cut off.

In the exemplary embodiment of FIG. 1, a motor and a CPU both receivepower from the battery. In the exemplary embodiment, during a 20 msec(milli-second) time period while the motor is running 116, the motor isdriven 118 by a high current pulse for 15 msec. In some embodiments,while the power source is driving 118 the motor, the voltage output ofthe power source may fall below the required input voltage of the CPU.Optionally, the CPU circuit may include power storage (for examplecapacitance) and the CPU voltage may be maintained 120 during the motorpulse by power draining from the capacitance of the CPU circuit.

Optionally, for the remaining 5 msec of the period, power to the motoris cut 122. In the example, when power to the motor is cut 122, the onlydrain on the power source is charging 114 a low current CPU circuit.With a low current drain on the power source, the power source mayoptionally provide a high voltage potential output. In some embodiments,while the current output from the battery is low, then the CPU circuitis charged 114 at a high voltage potential.

A System for Powering Two Devices

FIG. 2 illustrates an exemplary embodiment of a system for poweringmultiple devices. In the exemplary embodiment, a CPU 232 and a motor 238receive power from batteries 226. Optionally, a motor circuit 241 aincludes a motor driver 242 which distributes current to motor 238 intopulses. During the pulses, the high load on batteries 226 may reduce thevoltage output of batteries. Between pulses, the voltage output maysurge upward. Optionally, a CPU powering circuit 241 b may include avoltage regulator 240 to protect CPU 232 from high voltage surges and/oran energy reservoir 239 to smooth voltage between the surges, preservinga relatively constant high voltage power to the CPU.

In the exemplary embodiment of FIG. 2, a power source may include forexample a set of three Silver Oxide (Ag2O) batteries 226. In someembodiments, three fresh Ag2O batteries 226 may have a reliablecontinuous output of 4.5 V at current of up to 12 mA for up to 100hours.

In the exemplary embodiment of FIG. 2 it may be desired to use batteries226 to simultaneously power motor 238 drawing 150 mA at start up and 50mA while running. In the exemplary embodiment of FIG. 2, a CPU may havea current requirement of 0.3 mA and a voltage reset threshold of 2.4 V.

In some embodiments, when motor 238 is switched on (for example usingswitch 227) and runs continuously, the high current load of motor 238may cause the voltage output of battery 226 to drop below the resetthreshold of CPU 232.

In the exemplary embodiment of FIG. 2, motor driver 242 may include anoscillator 236. Optionally motor driver 242 may include a switch, forexample a FET 234. In the example of FIG. 2, oscillator 236 may send afixed pattern signal to FET 234 for alternatively driving pulses ofpower to motor 238 and cutting off power to motor 238. In the example ofFIG. 2, pulses of power may last for 15 msec and subsequently power tomotor 238 may be cut off for 5 msec. During the 15 msec driving period,the voltage output of batteries 226 may be reduced to between 1.5 and2.5 V. During the 5 msec cut off period, the voltage output of batteries226 may rise back to between 4.0 and 4.5 V.

In the embodiment of FIG. 2, energy reservoir 239 includes a capacitor230 and a restrictor 228. Optionally, during a voltage surge (forexample between pulses), capacitor 230 may store power. When voltagedeclines (for example when motor 238 is drawing a pulse of power frombattery 226), capacitor 230 may optionally feed the stored power to CPU232. In the embodiment of FIG. 2, capacitor 230 may be for example a 100μF capacitor. In some embodiments, the capacitance may range, forexample, between 20 and 300 μF. Optionally, restrictor 228 may include adiode. Restrictor 228 may prevent leaking of charge from capacitor 230to batteries 226 or to motor circuit 241 a.

In some embodiments, the combination of motor driver 242 and energyreservoir 239 may temporarily (for example for a time period rangingbetween 5 msec to 50 msec) maintain a voltage input to CPU above thevoltage of the power source of the CPU. This may optionally be donewithout a boost converter. Optionally, the voltage to the CPU may bemaintained above a threshold value even when the power source output(for example output of batteries 226) temporarily and/or cyclicallyfalls below the threshold.

In some embodiments, active cutting 122 of power occurs when the motoris running. Optionally, cutting may not occur when the motor is notrunning (for example during a sleep period wherein the CPU is running,but not the motor). In some embodiments, this may mean that the systemdescribed herein requires very little power during breaks when the motoris not running.

Voltage Vs. Time at the IC and at the Motor

FIG. 3A includes graphs of experimental results compared to hypotheticalcurve of Voltage and/or Current vs. time across an inertial device (forexample motor 238) and across an IC (for example CPU 232).

Various embodiments and aspects of the present invention as delineatedherein and as claimed in the claims section below find experimentalsupport in the example of FIG. 3A.

Reference is now made to the examples of FIG. 3A, which together withthe descriptions herein illustrate some embodiments of the invention ina non limiting fashion.

Some details of the exemplary experimental circuit used in FIG. 3 areshown in FIG. 7. The simulated portions of FIG. 3A illustrate that, forthe experimental setup, when the motor is connected directly to thebattery, the output battery voltage 326′ quickly drops to less than thereset threshold (2.4 V) of the IC. The experimental results illustratedin FIG. 3 show that with protection of a distributing motor driver (inthe example driver 442 [see FIG. 7]), a voltage regulator, (in theexample regulator 440440), and an energy reservoir (in the examplereservoir 439) the IC input voltage 332″ is maintained above the CPUreset voltage.

In FIG. 3A the lower graph shows the battery output voltage. A simulatedunloaded output voltage 326 of 4.5 V of three Ag2O batteries 226 isshown. A second simulated curve shows the output battery voltage 326′when connected directly to the motor. Very soon after the motor isturned on at t=5 msec 316, output battery voltage 326′ drops well below2.4 V. If a CPU having a reset threshold of 2.4 V were connected to thebattery with no protection, it could reset. An example of the effect ofdistributing motor input voltage (for example using driver 442) is seenin the experimentally measured battery voltage curve 326″. It is seenthat when the motor is activated the voltage 326″ is quickly reduced toless than 2.4 V. Nevertheless, during cut off periods, when the motor isnot drawing current, the voltage rises back to above 4 V.

In FIG. 3A, the upper graph shows the CPU input voltage. Simulated,voltage curve 332 shows the hypothetical voltage for a CPU connected toan unloaded battery and a low dropout voltage regulator (for example,regulator 440 which may include, for example, a LP2980 voltage regulatoravailable from Texas Instruments, Post Office Box 655303, Dallas, Tex.75265). Low dropout regulator 440 maintains the CPU voltage at 3.0 V aslong as the battery output voltage is greater than 3.0 V. When thebattery output falls below 3.0 V, low dropout regulator 440 may notboost the voltage. This can be seen in the hypothetical CPU inputvoltage 332′ which is indicative of the CPU voltage that would resultwithout redistributing battery output voltage 326′. In some embodiments,the CPU may reset when to voltage passes below a threshold (for example2.0 V), resetting the CPU may in some embodiments lead to the entiresystem shutting down. In such an embodiment, the curves 332′ and 326′may be replaced by, for example a line that starts like line 332 andgoes down to 2.0V (for example as approximately 8 seconds) and thenshuts down; after shutdown, voltage may optionally return to baseline.

An experimentally measured CPU input voltage 332″ illustrates the effectof adding a distributing motor drive (for example motor driver 442; seeFIG. 7) and simple capacitance energy reservoir (for example energyreservoir 439 see FIG. 7) to the system. Note that in the example, eventhough the power source (for example battery output voltage 326″) dropstransiently to less than 2 V, energy reservoir 439 maintains CPU inputvoltage 332″ above the 2.4 V cutoff voltage threshold.

Multi-Scale Time Considerations

FIGS. 3B, 3C and 3D are graphs of simulated voltage 326″ data at thebattery illustrating some exemplary changes in voltage at a fewdifferent time scales.

FIG. 3B illustrates an exemplary simulated voltage 326″ over time for abattery on a time scale of the time slicing (for example over 50 msec).For example, two 15 msec pulses are shown and two 5 msec motor cut offperiods are shown. During each motor cut off period there is a voltagesurge 325.

FIG. 3C is a graph illustrated an exemplary motor-on period of 200 msec.Optionally, during the motor-on period, the power is sliced between amotor and an integrated circuit. In the example of FIG. 3C, during the200 msec motor-on period, there are 10 slicing periods, each slicingperiod having for example a 15 msec pulse of power to the motor and a 5msec period where power to the motor is cut. Optionally, during the 10power cutting periods, there occur 10 voltage peaks 325. Following themotor-on period there is a motor-off period. The duty cycle of theslicing may be defined as the length of the pulses during an on perioddivided by the length of the on period. For example in the illustration10 pulses of 15 msec each over a 200 msec on period give a duty cycle of10*15/200=0.75 or 75%. Optionally, the length of the pulses and/or thecutting off periods need not be fixed. For example, the length of thepulses and/or the cutting off periods may vary during and/or between onperiods.

FIG. 3D is a graph illustrating an exemplary embodiment of pulse densitymodulation (PDM) wherein on 200 msec periods are spread among 1800 msecsleep periods when the motor is off. In FIG. 3D there is illustratedthat is some cases there may be a slow degradation of the batteryvoltage. Slow degradation may be caused, for example, by chemicalfatigue of the battery, for example due to slow diffusion of ions acrossa semi-permeable membrane. In the example of FIG. 3D, the batterypartially recovers during the off periods of the PDM, but the offperiods are not long enough for full regeneration of the battery.

FIG. 3E is a schematic illustration of an exemplary embodiment of PDM,wherein fixed time length motor-on periods are spread among varying timelength sleep periods (when the motor is off). Optionally, the amount ofwork done by the motor may be controlled by adjusting the length of thesleep periods. For example, the rate of pumping of a medicine may bedependent on the density of the on periods (for example in FIG. 3E thereare six 200 msec on periods during 10 sec for a density of 0.12).

A Medical Infusion Device

FIG. 4 is a block diagram illustration of an exemplary embodiment of adisposable portable medical infusion pump employing an exemplaryembodiment of a power distribution system. The exemplary infusion systemmay be designed to be cheap, disposable, small and reliable. Optionally,the system may include a motor driven pump that requires a high currentwhen it is running. Optionally, the system may include a controllerwhich requires a stable input voltage. In some embodiments, a cheap,small, disposable power supply (for example three Ag2O batteries) maynot be able to simultaneously supply both requirements directly.

In some embodiments, an infusion pump may be employed to inject amedication slowly over a long period of time. In this mode thecontroller may optionally run for a long time to keep track of injectionprogress. Optionally, the pump may be activated only for relativelyshort periods to supply incremental injections separated by large timeintervals. For example, in such a case, a small increase in the powerrequirements of the controller while the motor is not running may causea significant drain on the energy of the power supply.

In some embodiments it may be desirable to supply an energy reservoirfor the controller. Optionally, it may be desirable that the reservoirbe able to supply a dependable voltage to the controller even when themotor is running. Optionally, it may be desirable that the reservoir beable to supply a dependable voltage to the controller even when thevoltage output of the battery drops below a reset threshold of thecontroller. Optionally, it may be desirable that the energy reservoirnot significantly increase the power consumption of the controller whenthe motor is not running.

In the example of FIG. 4, optionally a motor 438 drives a pump (notshown) injecting a medication. The rate of injection is optionallycontrolled using a micro controller 432. Controller 432 may optionallyinclude an oscillator 451 and a real time clock 455.

In the exemplary embodiment of FIG. 4, controller 432 receives powerfrom batteries 426 through voltage regulator 440 and energy reservoir439. Energy reservoir 439 may optionally include a capacitor and/or arestrictor for example as illustrated in FIG. 8. Optionally, batteries426 may also drive motor 438 via motor driver 442. Optionally,controller 432 controls motor 438 via motor driver 442. For example,motor driver 442 may include a FET and controller 432 may control thegate voltage to distribute the current to motor 438 in pulses.

In some embodiments, controller 432 may receive input signals indicatingthe status of the injector. For example: a current sensor 454 may reportthe current flowing to motor 438; a rotation sensor 452 may be used totrack the rotations of the motor 438 and quantity of medicine injected.

In some embodiments, the medicine may be administered by repeated smalldoses. For example, the controller 432 may drive motor 438 for a 300msec dosage period, measure the number of rotations, compute thequantity injected and determine a waiting time for next dosage in orderto meet a stored injection rate and then wait and afterwards injectagain for 300 msec. For some delivery rates, the waiting period betweendoses may for example range between 500 msec to 5 sec. For lowerdelivery rates the waiting period may range between 3 sec and 5 minutes.In the waiting period, the injector may be in a sleep mode. For example,in the sleep mode the controller 432 may remain active, measuring timeuntil the next dosage and remembering the delivery parameters, but themotor 438 may be inactive. Optionally, the status indicators and/or thedelivery parameters may be stored in a volatile memory 449. In someembodiments, it may be important that the controller 432 not reset. Forexample, resetting may cause loss of parameter values stored in avolatile memory. For example, resetting of the controller 432 mayindicate a malfunction of the injector or cause a fault in the trackingof the injection, in some cases such a malfunction may for the patientto rush to the hospital or even endanger the patient's life.

In some embodiments, during the dosage period, the high current drawn bymotor 438 may cause the voltage output of batteries 426 to drop belowthe reset threshold of controller 432. Optionally, reset of controller432 may be avoided by commanding driver 442 to drive motor 438 withcurrent pulses (for example in a manner similar to FIGS. 2 and 3). Thismay be achieved for example by controller 432 sending pulsed controlsignals to the FET of driver 442.

Alternatively or additionally, a boost regulator may be used to maintaincontroller input voltage greater than the voltage of the power source.Boost regulators may be inefficient and/or expensive in comparison tosome embodiments of current redistribution. For example, in sleep modethe controller 432 may continue running from the battery output whichmay be greater than 3.0V while motor 438 is not be running. Under suchconditions, a boost regulator inefficiently continues to draw power. Incontrast, in some embodiments of a current distribution system, thedistribution of the motor input may not be active during sleep mode.Optionally, under those conditions, the distribution system may notsignificantly increase the energy consumption of controller 432. In someembodiments (for example see FIG. 9), current redistribution (forexample, using motor driver 442 to create cut off power to motor 438thereby creating voltage spikes and using energy reservoir 939 topreserve a threshold voltage to controller 432) may be used for slowdelivery rates (where, for example, energy consumption of the controllerduring sleep mode is important) and a boost regulator (for exampleregulator 940) may be used for high delivery rates (where, for examplethe sleep time is short and the inefficiency of having a boost regulatoron the controller circuit may not be critical).

Optionally the infuser may include a communication cradle 448. Cradle448 may be used, for example, to program a delivery rate for a drug.Optionally cradle 448 may also be used to adjust control parameters suchas the length of a dosage period, the rate of current distribution. Forexample, for highly viscous drugs, motor 438 may draw more current whileinjecting the drug. Optionally for more viscous medicines, the length ofdistributed pulses may be reduced and/or the length of the dosage periodmay be reduced to avoid loss of voltage to controller 432.

In some embodiments, the system may include a non-volatile memory 447(FIG. 4). The non-volatile memory 447 may store, for example,pre-programmed information programmed into the infuser using cradle 448.Optionally, the preprogramming may be done while being prepared for use,for example by the manufacturer and/or a doctor and/or a hospitalemployee and/or a pharmacist. Alternatively or additionally, thenon-volatile memory 447 may include performance flags. Optionally flagvalues may be recording during operation and/or before shut down. Whenthe infuser restarts, the flag values may be used to adjust parameters,for example, to improve operation and/or avoid repeated unintentionalshut downs and/or to recognize a repeated malfunction.

In some embodiments the infuser may include dynamic adjustment ofoperating parameters. For example, the infuser may be able to adjustitself to adapt to conditions or performance parts that may not be knowna-priori. For example, if the infuser is stored for a long timebatteries 426 may not perform according to specifications. For example,if the infuser is used under cold conditions, the viscosity of themedicine may increase and the performance of batteries 426 may be poor.In such a case, during a dosage period, motor 438 may draw higher thanexpected current. In such a case, during a dosage period, the drop ofvoltage output of battery 426 may be more than expected. Optionally theinfuser may include sensors (for example current sensor 454 and/or avoltage sensor [not shown]) to detect such changes in performance anddynamically adjust operating parameters (for example by shortening thedosage period or shortening the pulse length of the currentdistribution) to allow the infuser to continue operation and avoidmalfunction.

In some embodiments, the performance characteristics of the infuser maybe adjusted for secondary reasons. For example the rate of pulses may beadjusted to achieve a desired vibration (patients may feel moreconfident that the device is working if they hear a reassuring hummingsound).

Controller 432 may optionally include a watch dog 453 to preventuncontrolled injection upon failure of the controller. The injector mayinclude optional user indicators 450 for example a malfunction alarmand/or an operating indicator LED. The injector may optionally includeuser controls 446 such as an activator button.

In some embodiments, the voltage distribution cut off period may have alength of, for example, between 2 and 50 msec. In some embodiments, thevoltage distribution pulse to motor 438 may have a length of, forexample, between 2 and 150 msec. In some embodiments, the duty cycle ofthe power distribution (pulses and cut offs) may range between 50% and95%. In some embodiments, the pulse density modulation motor control mayhave a motor-on time ranging between 50 and 500 msec. In someembodiments, the pulse density modulation motor control may have amotor-off time ranging between 500 and 5000 msec. In some embodiments,the pulse density modulation motor control may have a duty cycle rangingbetween 2% and 20%.

Method of Dynamically Controlling a System Powering Two Devices

FIG. 5 is a flow chart illustration of a method for dynamicallyadjusting performance characteristics of a system for powering twodevices with a single power source. Particularly in the example of FIG.5, based on pre-stored parameters and/or on the output of varioussensors, a controller adjusts parameters of various aspects of currentdistribution and/or motor control.

In some embodiments operating parameters may be adjusted at start upbased on parameters programmed into a non-volatile memory. Alternativelyor additionally, the non-volatile memory may include flags which are setduring operation. For example if the controller resets during operation,flag values may optionally be read upon restart and used to adjust thesystem operating parameters.

In some embodiments, operating parameters may be adjusted dynamicallyduring operation. For example, the parameters may be adjusted accordingto sensor outputs.

In the embodiment of FIG. 5, upon start up 556, the controller makes aself check 560. The self check may optionally include checking 562 avarious components for malfunctions. If there is a malfunction, amalfunction procedure 584 may optionally be initiated. For example,alarm may sound, an LED may be lit, and/or the infuser may shut down.

Alternatively or additionally, the self check may include checking 562 bstored flags for a sign the injector had been activated previously andshut down and the current start up 556 is a restart. Optionally, storedflag values may be read 563 to determine the cause of the previous shutdown. For example, the malfunction flags could indicate that there was ahigher than expected current drain from the motor and/or that thebattery performed worse than expected; this could be a sign of, forexample, cold temperatures (that may increase medicine viscosity anddecrease battery performance). According to the cause of the previousshut down, actions may optionally be taken to adjust 564 the operatingparameters of the pump to avoid further malfunctions. Adjustments 564may optionally include those listed above with respect to dynamicadjustment of operating parameters. Optionally, a restart flag may beset 566. In some embodiments, if the system fails again, the system willknow that the system has been reset previously; for example this couldbe a sign of a serious malfunction.

In the exemplary embodiment of FIG. 5, parameters have been properlyadjusted 564 and/or on a normal start, the injector may optionally wait517 (for example until a prescribed injection time) and/or then start516 the motor to inject the medicine.

In some embodiments, while the medicine is being injected, the currentto the motor may be measured 572. Optionally, based on the measurementresults operation of the pump may be dynamically adjusted.

For example, if the current is greater than a maximum threshold 574,there may be an occlusion 580. The controller may optionally performmalfunction procedure 584.

For example, if the current is less than a minimum threshold 576, thedoor of the pump may be open 586. The controller may optionally set adoor open flag 588, notify the user 589, and/or restart the system fromthe self check 560.

For example, if the voltage to the controller is dropping at a rategreater than a maximum threshold 578, the battery may be old 590. Thecontroller may optionally set a flag 592 and/or adjust 594 operatingparameters before the next cycle 596.

Setting flag 592 may include for example saving performance and/oroperational parameters to a non-volatile memory. Optionally, the storedparameters may include for example, the amount of medicine injecteduntil now, the rate of injection, the measured voltage input to the CPUand/or the rate of change of voltage input to the CPU. There mayoptionally also be cumulative stored values, for example the amount ofmedicine injected may be stored in a nonvolatile memory periodicallyand/or when there is danger that the volatile memory will be reset (forexample when the voltage to the CPU drops to near the reset threshold).If the CPU is reset, then upon restart 562 b the stored injection volumemay be used as the initial volume (thus treatment will be cumulativeover restarts and the patient will not receive an overdose if the systemshuts down and restarts and repeats the full dose).

Optionally, the stored parameters may be used by the controller forexample in order to adjust the operating parameters on restart forexample in order to avoid repeating the malfunction. Alternatively oradditionally, the stored parameters may be used by technical and/ormedical staff (for example avoid future malfunctions and/or to adjustthe continued treatment of the patient).

Adjustments

Some example of adjustments 594 to operational parameters that may bemade dependent on current measurements 572 and/or adjustments 594,564may be made dependent on operational parameters read 563 from storedmeasurements. Adjustments may include, for example, one or more of:

-   -   if the measured voltage to the CPU dipped too low, then the duty        cycle of the current distribution may be reduced;    -   if the voltage to the CPU during cut off times is greater than a        cutoff voltage target level (e.g. well above the reset threshold        of the CPU) but voltage is to the CPU is low at the end of the        drive pulse to the motor, (in some embodiments this may mean        that there is not enough storage capacity [for example capacitor        230 is too small]) then the drive pulse length may be made        shorter;    -   if the voltage during the cut off period does not rise to the        target level than the cut off period may be lengthened;    -   if the cut off period has been lengthened to a stored maximum        cut-off period value, and the voltage still does not rise to the        target level, then the motor-on time may be reduced;    -   if the voltage is dropping too much over the long term, the        density of the PDM may be reduced (in some embodiments, this may        reduce the power output of the device [for example a pumping        rate of an infuser]).

Measurements of Current and Voltage During the Distribution Cycle

Various embodiments and aspects of the present invention as delineatedherein and as claimed in the claims section below find experimentalsupport in the example of FIG. 6.

Reference is now made to the examples of FIG. 6, which together with thedescriptions herein illustrate some embodiments of the invention in anon limiting fashion.

Some details of the experimental circuit used in FIG. 6 are shown inFIG. 7. FIG. 6 is a graphical illustration of experimental results for asystem similar to that illustrated in FIG. 7. Experimental measurementsof voltage 326″ and current 626 input to the motor are shown.

Lines 672 illustrate measurement times for current at the motor. In theexemplary experiment, current was measured during the stable phase ofthe movement. Current was measured 10 msec after activation the motorwhen the voltage drain stabilized (for example, at start up a DC motormay draw a transient high current of 250% the working current of themotor). In the exemplary experiment, measurements were made near themiddle of the motor driving pulse for ten consecutive pulses.

Circuit Details of a Exemplary Embodiment

FIG. 7 illustrates details of an exemplary embodiment wherein controller432 controls switching and distribution of power to motor 438.Optionally, power is supplied from batteries 426 to controller 432 via aCPU circuit 741 b. Optionally, power is supplied from batteries 426 tomotor 438 via a motor circuit 741 a.

In some embodiments, controller 432 sends control signals to a FET 734to drive motor 438 and/or cut off power. Optionally, controller 432 mayuse driver 442 to turn motor 438 on or off, and/or to pump a medicine ata controlled rate. Alternatively or additionally, controller may usedriver 442 to distribute power input to motor 438 in order to maintainsufficient voltage to controller 432.

In the exemplary embodiment of FIG. 7, voltage regulator 440 and energyreservoir 439 may optionally smooth voltage surges to supply a smoothvoltage to controller 432. Optionally, reservoir 439 may include arestrictor 728 and a capacitor 730.

Optionally a controller interface is supplied by input cradle 448.Optionally, dynamic adjustment of operation may be based on inputs fromrotation sensor 452 and/or current sensor 454. Alternatively oradditionally, operation of the embodiment of FIG. 7 may be fixed.Alternatively or additionally, the embodiment of FIG. 7 may include someor none of sensors 452 and 454. Alternatively or additionally, theembodiment of FIG. 7 may include more sensors.

440 FIG. 8 includes even more circuit details of an exemplary embodimentof a voltage regulating system. Parts having similar function to partsof the embodiments of FIGS. 2, 4 and 7 are marked with the same numbers.

Device with an Optional Boost Regulator

FIG. 9 is a circuit diagram of an exemplary embodiment of a system forpowering multiple devices. The exemplary embodiment of FIG. 9 includesan optional motor circuit 941 a. Motor circuit 941 b may, optionallysupply pulsed and/or unpulsed power from batteries 426 to motor 438. Theexemplary embodiment of FIG. 9 includes an optional CPU circuit 941 b.CPU circuit 941 b may, optionally supply power from batteries 426 tocontroller 432.

CPU circuit 941 b may, optionally include an energy reservoir 939 and/ora boost regulator 940. Reservoir 939 may include an optional restrictor928 including an active FET gate that may prevent high voltage powerfrom draining from capacitor 730 to battery 426 and/or motor 438.

Boost regulator 940, may for example, maintain a voltage above a resetthreshold for controller 432 even when the voltage output of battery 426falls below the threshold voltage for an extended period.

Reservoir 939 may optionally maintain a voltage above a reset thresholdfor controller 432 when the voltage output of battery 426 falls belowthe threshold voltage for a short period. For example, when there is alow density PDM (for example as illustrated in FIG. 3A-E), FET 934 maybe switched closed, and energy reservoir 939 may optionally maintain adesired threshold voltage to controller 432 by means of currentdistributing similar to that describe with respect to FIGS. 2, 3A-Eand/or 4.

Optionally, active FET gate current restrictor 928 may prevent leakageof current from capacitor 230 to battery 426 and/or motor driver 442.For example, when voltage of battery 426 is low, controller 432 mayclose the gate of restrictor 928. For example, closing restrictor 928may be in reaction to detecting low battery voltage via a voltage sensoracross battery 426 (not shown). Alternatively or additionally, switchingof restrictor 928 may be controlled by timing software. For example, thetiming software may close restrictor 928 when FET 734 is open to supplyhigh current to motor 438. Optionally controller 432 may then reopenrestrictor 928 a few milliseconds after closing FET 734 (when it can beassumed that the voltage of battery 426 has risen above the cutoffthreshold). Alternatively or additionally the embodiment of FIG. 9 mayhave include only some or none of the optional sensors 452, 454, 952.

In some embodiments, at some times, boost regulator 940 may be used tomaintain voltage of controller 432. For example, boost regulator 940 maybe used when voltage sensor 952 senses that voltage to controller 432 isdropping too low (for example, either voltage drops below a dangerthreshold and/or the voltage does not rise sufficiently when power tomotor 438 is cut). Alternatively and/or additionally boost regulator 940may be used when the pumping schedule is fast for example as illustratedin FIG. 10 and the accompanying explanation.

In some embodiments, when boost regulator 940 is in use, FET 934 isswitched open and restrictor 928 is switched closed. Optionally boostregulator 940, may provide a high voltage input current to controller432 even when the voltage of battery 426 falls below the threshold foran extended period. Optionally, when boost regulator 940 is in use,motor driver 442 may not be used for distributing power. For example,FET 734 may be switched on or off according to the needs of motor 438and the required power output (for example, for a medical infuser, tocontrol the pumping rate) without regard to the voltage input tocontroller 432.

High Rate Power Output

FIG. 10 illustrates voltage of time for example of driving a circuit ata high power output. In the exemplary embodiment of FIG. 10, the resttime of 750 msec between motor-on events of 350 msec is not enough timefor the battery to regenerate to its full output. When there is notenough recovery time, battery voltage may, for example, decay over time.In the example of FIG. 10, the battery voltage may drop below a batteryreset threshold (for example 2.4 V) and remain below the threshold forextended periods.

In the embodiment of FIG. 10, redistribution of current (as illustratedfor example in FIGS. 1, 2, 3 and 4) may not be an efficient manner tomaintain the voltage input of an integrated circuit above a resetthreshold. Optionally, a boost regulator (for example boost regulator940 of FIG. 9) may be used to maintain a high voltage potential for anintegrated circuit (for example controller 432).

In FIG. 10, simulated battery output voltage 1026 is shown over time,for an exemplary embodiment. In the exemplary embodiment of FIG. 10,during motor-on events (in the example of FIG. 10 from 0-350 msec, from2000-2350 msec, from 4000-4350 msec and from 6000-6350 msec) thebatteries are drained and during the off events the batteries regenerateuntil they reach a peak 1025 a, 1025 b, 1025 c, 1025 d right before thenext on event.

A possible disadvantage of use of boost regulator 940 is that the boostregulator 940 may consume power. For example, controller 432 may consume0.5 mW of power. When power is supplied to controller 432 through boostregulator 940 the combination circuit may require 0.75 mW of power.

In cases where the device may continue to function for long periods oftime (for example to slowly inject a drug), a small increase of powerconsumption of the CPU may be significant. The loss of energy due to useof a boost regulator may then be significant. Slow injection may, forexample, use a small PDM duty cycle (for example as illustrated in FIG.4A-E) wherein short cut periods may restore a battery output voltageabove the CPU reset threshold. Optionally, in such a case, powerdistribution may be the preferred way of regulating voltage.

In the example of FIG. 10, during long periods where the battery outputvoltage remains below the CPU input threshold, (for example in FIG. 10from 4000 msec until 5000 msec and from 6000 msec until 8000 msec) aboost regulator (for example boost regulator 940) may be used tomaintain CPU input voltage. At other (for example from 0-4000 msec andfrom 5000-6000 msec) the boost regulator may be bypassed (for example byclosing FET 934 and a CPU input threshold voltage may be maintainedusing a power distribution regulator system (for example, duringmotor-on events, using motor driver 442 to cut of power periodically tothe motor and capacitor 230 to store energy and keep up the CPU voltagewhen the voltage output of the battery falls for short periods below thethreshold).

General Notes

It is expected that during the life of a patent maturing from thisapplication many relevant technologies will be developed and the scopeof the various terms in the application are intended to include all suchnew technologies a priori.

As used herein the term “about” refers to ±5%

The terms “comprises”, “comprising”, “includes”, “including”, “having”and their conjugates mean “including but not limited to”.

The term “consisting of” means “including and limited to”.

The term “consisting essentially of” means that the composition, methodor structure may include additional ingredients, steps and/or parts, butonly if the additional ingredients, steps and/or parts do not materiallyalter the basic and novel characteristics of the claimed composition,method or structure.

As used herein, the singular form “a”, “an” and “the” include pluralreferences unless the context clearly dictates otherwise. For example,the term “a compound” or “at least one compound” may include a pluralityof compounds, including mixtures thereof.

Throughout this application, various embodiments of this invention maybe presented in a range format. It should be understood that thedescription in range format is merely for convenience and brevity andshould not be construed as an inflexible limitation on the scope of theinvention. Accordingly, the description of a range should be consideredto have specifically disclosed all the possible subranges as well asindividual numerical values within that range. For example, descriptionof a range such as from 1 to 6 should be considered to have specificallydisclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numberswithin that range, for example, 1, 2, 3, 4, 5, and 6. This appliesregardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to includeany cited numeral (fractional or integral) within the indicated range.The phrases “ranging/ranges between” a first indicate number and asecond indicate number and “ranging/ranges from” a first indicate number“to” a second indicate number are used herein interchangeably and aremeant to include the first and second indicated numbers and all thefractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the present invention. To the extent thatsection headings are used, they should not be construed as necessarilylimiting.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

1-35. (canceled)
 36. A method for increasing a voltage potentialavailable to a high voltage device sharing a power source with a highcurrent device comprising: producing transient high voltage surges inthe output of the power source by repeatedly cutting off power to thehigh current device during predetermined spaced apart time periods;storing energy during said surges; releasing said stored energy when avoltage output of said power source falls below a threshold voltageneeded to maintain functioning of said high voltage device.
 37. Themethod of claim 1 wherein the high voltage device is comprised of atleast one of an integrated circuit, a CPU, and a processor.
 38. Themethod of claim 1 wherein the high current device is comprised of aninertial device such as an actuator or a motor.
 39. The method of claim1 wherein the power source is comprised of at least one battery.
 40. Themethod of claim 1, wherein said cutting off of power to the high currentdevice is controlled by the high voltage device.
 41. The method of claim1, further comprising: preventing leakage of said released energy awayfrom the high voltage device.
 42. The method of claim 1, wherein saidrepeatedly cutting off of power to the high current device has a periodof between 5 and 50 milli-seconds.
 43. The method of claim 1, whereinsaid repeatedly cutting off of power to the high current device has aduty cycle of between 50% and 95%.
 44. The method of claim 1 furthercomprising: pumping a medicine with said high current device; andcontrolling a rate of said pumping with the high voltage device.
 45. Themethod of claim 9, wherein said controlling is adjusted for maintainingsaid threshold voltage to the high voltage device accounting for anoutput limitation of the power source and a limit of said storage. 46.The method of claim 9, wherein said controlling is by pulse densitymodulation.
 47. The method of claim 11, wherein said pulse densitymodulation has a pulse width of between 50 and 500 milli-seconds. 48.The method of claim 11, wherein said pulse density modulation has a dutycycle of between 2% and 20%.
 49. The method of claim 1, furthercomprising: testing a voltage input to said high voltage device; andadjusting said cutting off of power to the high current device accordingto a result of said testing to maintain the input voltage to said highvoltage device at or above said threshold voltage.
 50. A system fordistributing power among a plurality components of a portable devicecomprising: a first circuit powering a high current device; a secondcircuit powering a high voltage device; and a power distributorconnected to a power source, said power distributor configured to;supply to said first circuit, higher current pulses of power from saidpower source having sufficient energy to power said high current device,and at least partially cut off power to said first circuit between saidpulses to produce voltage surges having sufficient energy to power saidhigh voltage device at a higher voltage potential than the potential ofsaid higher current pulses.
 51. The system of claim 15, furthercomprising: an energy storage device connected to said second circuit,said energy storage device configured to store energy at a high voltageduring said voltage surges, and release said stored energy to the highvoltage device between said voltage surges.
 52. The system of claim 15,further comprising: a sensor to sense a voltage input to said highvoltage device and wherein said high voltage device is configured toadjust said distributer in response to an output of said sensor topreserve a threshold voltage to the high voltage device sufficient forfunctioning of the high voltage device.
 53. The system of claim 15,wherein said high current device has an inertia to keep operating duringan inertial period and wherein said distributer is configured to keep alength of a cut off period of power to the high current device betweensaid high current pulses less than a length of said inertial period. 54.The system of claim 15, further comprising: a voltage sensor configuredto measure an input voltage to said high voltage device and wherein saidhigh voltage device is configured to receive output from said sensor andto adjust said distributor in response to said output of said sensor tomaintain said input voltage to the high voltage device to be greaterthan a threshold value.
 55. The system of claim 19, wherein saidadjusting includes at least one action selected from the groupconsisting of: lengthening a period of said cutting off of the power tothe high current device in response to a low value of said voltage inputmeasurement, shortening a period between said cut off periods inresponse to a low value of said voltage input measurement, reducing aduty cycle of said high current device in response to a low value ofsaid voltage input measurement, lengthening a period of said cutting offof the power to the high current device in response to a low value ofsaid voltage output measurement, shortening a period between said cutoff periods in response to a low value of said voltage outputmeasurement, and reducing a duty cycle of said high current device inresponse to a low value of said voltage output measurement.